The invention relates to a system for deflecting through-the-flowline ("TFL") tools from a main flowline into a selected branch line.
Large multi-well subsea oil and gas production systems are generally associated with a subsea manifold at which their production is commingled in a common main flowline which delivers the accumulated oil and gas production to a surface process facility.
At times it is necessary to undertake downhole maintenance of the wells using TFL tool pumpdown techniques. In such operations a tool designed to perform a specific function, such as replacement of a downhole component, is assembled in an articulated TFL tool string at the surface facility. The tool string is then inserted into a special lubricator at the surface facility and pumped via the main flowline into a selected branch line and the associated well.
Numerous systems have been developed for deflecting TFL tools from a main flowline into a selected branch line. U.S. Pat. Nos. 3,545,489; 3,599,711; 3,664,376; 4,252,149; 4,224,986; 4,291,742 and 4,312,378 and U.K. Patent Nos. 1,321,684 and 2,170,579 disclose permanently installed diverters that are able to deflect a TFL tool into a selected branch line. The disadvantages of these diverters are that they require provisions to facilitate maintenance of the diverter and its actuator and that means for remotely switching the diverter must be provided.
An object of the present invention is to remedy these drawbacks and to provide a system for deflecting TFL tools without permanently installed deflector assemblies such that a simple and cheap flowline system is created which requires a minimum of maintenance.